Fatty acid diesters

ABSTRACT

Fatty acid esters for use in cosmetic compositions are prepared having the formula 
     
         CH.sub.3 (CH.sub.2).sub.5 CH(OCOR.sub.1)(CH.sub.2).sub.10 COOR.sub.2 
    
     wherein, 
     R 1  is a straight chain hydrocarbon radical having 17 carbon atoms with 1 to 3 double bonds therein; and 
     R 2  is a straight or branched chain hydrocarbon radical having 5 to 22 carbon atoms.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to high molecular weight diesters containingunsaturated hydrocarbon chains.

2. Description of the Prior Art

Organic esters, having the structure R₁ COOR wherein R₁ and R areidentical or different hydrocarbon chains, are widely distributed innature and may be obtained from animal, vegetable and mineral sources.Such organic esters are in the form of liquid and solid fats, waxes andoils.

All natural fats and oils are mixtures of esters and are distinguishedby their melting point range; the oils are liquid at ambient temperaturedue to the high percentage of unsaturated hydrocarbons in theirmolecules; the fats are solid or semi-solid. The esters of fats andoils, called triglycerides, are built upon glycerol as the alcoholmoiety of the molecule, having the three hydrogens of glycerol replacedwith fatty acid radicals. The acids found in fats and oils are straightchain, saturated or unsaturated monocarboxylic acids with four totwenty-six carbon atoms.

Waxes are also mixtures of esters, but differ from fats and oils in thatthey are monoesters of various alcohols with fatty acids. Most waxes aresolids, containing large proportions of saturated fatty acids.

The organic esters are extensively used in cosmetic, household,industrial and pharmaceutical preparations. For example, the lowermolecular weight esters are used as solvents in lacquers and nailenamels, perfumery, medicines and artificial flavorings.

While most of the esters can be obtained from natural sources, manylower molecular weight esters and some waxes are also producedsynthetically. The synthetically produced esters are utilizedanalogously to the esters obtained from natural sources and are of greatcommercial importance.

An object of the present invention is to provide fatty acid esters basedon hydroxystearic acid.

Another object of the present invention is to provide fatty acid estersfor use in cosmetic compositions.

SUMMARY OF THE INVENTION

These and other objects are achieved by a fatty acid diester obtainedby: first esterifying a hydroxystearic acid with a long chainunsaturated fatty acid to form an unsaturated esterified fatty acid;then, reacting the unsaturated esterified fatty acid with a long chainfatty alcohol to produce a tri-fatty acid diester.

The fatty acid diesters of the present invention have the generalformula

    CH.sub.3 (CH.sub.2).sub.5 CH(OCOR.sub.1)(CH.sub.2).sub.10 COOR.sub.2

wherein

R₁ is a hydrocarbon radical having 17 carbon atoms with 1 to 3 doublebonds; and

R₂ is a hydrocarbon radical having 5 to 22 carbon atoms with straight orbranched chains.

Examples of fatty acid diesters of the present invention include:

Octyl Oleoyl Oxystearate

Ethylhexyl Linoleoyl Oxystearate

Isocetyl Oleoyl Oxystearate

Isocetyl Linoleoyl Oxystearate

Isostearyl Oleoyl Oxystearate

Isostearyl Linoleoyl Oxystearate

Octyl Linolenoyl Oxystearate

Isodecyl Linoleoyl Oxystearate

Isodecyl Oleoyl Oxystearate

Isodecyl Linolenoyl Oxystearate

Amyl Oleoyl Oxystearate

Amyl Linoleoyl Oxystearate

Octyldodecyl Oleoyl Oxystearate

Octyldodecyl Linoleoyl Oxystearate

DETAILED DESCRIPTION OF THE INVENTION

The fatty acid diesters of the present invention and synthesis thereofwill be illustrated by the examples that follow:

EXAMPLE 1 2-Ethylhexyl-12-Oleoyl Oxystearate

(A) 500 grams of 12-hydroxystearic acid (Union Camp-Cenwax A), 440 gramsof oleic acid (Emery-Emersol 233LL) and 7 grams of dibutyl tin oxide(Aldrich Chem. Co.) was mixed and heated to 190° C. in a 2-liter, 3-neckflask until the esterification reaction was completed. Water, which isformed during this esterification reaction was collected in a Dean-Starktrap. Upon completing the reaction, the acid number was determined andwas found to be between 99 and 106, and the molecular weight was 564 forthe product, 12-oleoyl oxystearic acid.

(B) 300 grams of 12-oleoyl oxystearic acid obtained in A above was mixedwith 90 grams of 2-ethyl-1-hexanol (Aldrich Chem. Co.). The mixture washeated to 180° C. and the water formed by the reaction was collected bya Dean-Stark trap. The reaction product, 2-ethylhexyl-12-oleoyloxystearate was carbon treated and filtered through a Buchner funnel.The acid number was found to be 6.5; while the saponification value was:166 calculated and 164.5 found.

It is to be noted, that the temperature used during the reaction may belowered, and the reaction time being from 2 to 10 hours, may beshortened by using a nitrogen sparge to drive water over during theesterification reaction.

EXAMPLE 2 2-Ethylhexyl-12-Linoleoyl Oxystearate

The preparation of the title compound is analogous to the preparation of2-ethylhexyl-12-oleoyl oxystearate, except that, instead of oleic acid,linoleic acid (Emery's Emersol 315) was used.

Analysis of the title compound gave an acid number of 3 and asaponification value of 166.

EXAMPLE 3 Isostearyl-12-Linoleoyl Oxystearate

The title compound was prepared using 12-linoleoyl oxystearic acid andisostearyl alcohol (Aldo 66-Sherex co.) according to the proceduredescribed in Example 1.

The acid number was found to be 7, while the saponification value was136.

Compounds of the present invention were found to have an oral toxicityin rats of greater than 15.9 ml/kg; skin irritation index was 0.1; andthe Draize test showed a minimal conjunctival irritation which clearedby day two.

The compounds of the present invention may be easily formulated intocosmetic compositions, household and pharmaceutical products.

In general, a cosmetic formulation for skin care comprises the followingingredients by weight:

1-20% of a fatty acid diester of the present invention or mixturesthereof;

5-10% of a humectant, such as glycerin, propylene glycol, sorbitol andmineral oil;

0.2-1.0% of a thickener, such as carboxyvinyl polimers, methylcellulose, hydroxymethyl cellulose and hydroxypropyl cellulose;

0.5-10% of an emulsifier, such as sorbitan stearate, sorbitan palmitate,glyceryl stearate and glycol stearate; and

50-80% water.

In addition other ingredients, conventionally used in cosmeticpreparations, may be used, such as preservatives, coloring agents andperfumes.

Examples 4, 5, 7 and 8 illustrate the cosmetic compositions of thepresent invention.

EXAMPLE 4 Cosmetic Cream

    ______________________________________                                                          % w/w                                                       ______________________________________                                        Octyl 12-oleoyl oxystearate                                                                        8.00                                                     Mineral Oil         10.00                                                     Glycerol Monostearate                                                                             10.00                                                     Methyl Paraben       0.10                                                     Propyl Paraben       0.15                                                     Perfume              0.25                                                     Water               71.50                                                     ______________________________________                                    

Comparative testing was performed in order to evaluate desirableattributes of a cosmetic cream containing a diester of the presentinvention. Example 5 shows the composition containing therein ethylhexyloleoyl oxystearate according to the present invention, while thecomposition of Example 6 contains a currently marketed ester.

EXAMPLE 5 Cosmetic Cream

    ______________________________________                                                           % w/w                                                      ______________________________________                                        Water                61.25                                                    Carbopol 934 Solution                                                                              5.00                                                     Ethylhexyl Oleoyl Oxystearate                                                                      8.00                                                     Propylene Glycol     7.00                                                     Methyl Paraben       0.30                                                     Propyl Paraben       0.10                                                     Glyceryl Stearate    4.00                                                     Cetyl Alcohol        1.20                                                     Stearic Acid         2.40                                                     Mineral Oil          8.00                                                     Steareth 20          1.00                                                     Triethanolamine      1.40                                                     Trisodium EDTA       0.05                                                     Quaternium 15        0.10                                                     Dimethicone          0.20                                                     ______________________________________                                    

EXAMPLE 6 (Comparative Example) Cosmetic Cream

    ______________________________________                                                        % w/w                                                         ______________________________________                                        Water             61.25                                                       Carbopol 934 Solution                                                                           5.00                                                        Isopropyl Myristate                                                                             8.00                                                        Propylene Glycol  7.00                                                        Methyl Paraben    0.30                                                        Propyl Paraben    0.10                                                        Glyceryl Stearate 4.00                                                        Cetyl Alcohol     1.20                                                        Stearic Acid      2.40                                                        Mineral Oil       8.00                                                        Steareth 20       1.00                                                        Triethanolamine   1.40                                                        Trisodium EDTA    0.05                                                        Quaternium 15     0.10                                                        Dimethicone       0.20                                                        ______________________________________                                    

Consumer evaluation tests were performed by first cleaning the forearmsand hands with ivory soap and water and dried. The products were appliedto alternate forearms and hands and evaluated for feel, consistency,spreadability, absorbance, and afterfeel. They were judged also forsuitability as a hand cream based on the above parameters. Test resultsare shown in Table I.

                  TABLE I                                                         ______________________________________                                        Parameter    Example 6     Example 5                                          ______________________________________                                        Thickness    More viscous  Thinner, Flows                                                                easily                                             Consistency  Medium        Light                                              Spreadability                                                                              Glides/Waxy   Glides/Oily                                        Absorbency   Moderate      Moderate                                           Afterfeel    Moist         Moist                                                           Very Soft     Soft                                                            Very Silky    Silky                                              ______________________________________                                    

While both products are acceptable for use as hand creams in providingmoisturizing benefit, smoother and silky-feeling, the use of ethylhexyloleoyl oxystearate of Example 5 produced an oily feel whereas theisopropyl myristate of Example 6 felt waxy.

EXAMPLE 7

Another formulation which provides a thicker hand cream than example 5is a follows:

    ______________________________________                                                           % w/w                                                      ______________________________________                                        Isocetyl Linoleoyl Oxystearate                                                                     8.00                                                     Cetyl Alcohol        1.00                                                     Mineral Oil          10.00                                                    Glyceryl Monostearate                                                                              10.00                                                    Methyl Paraben       0.10                                                     Propyl Paraben       0.15                                                     Perfume              0.25                                                     Water                70.50                                                    ______________________________________                                    

EXAMPLE 8

This example illustrates the compatibility of the diesters with othercosmetic ingredients: the formula contains both a suntanning agent and asunscreening agent.

    ______________________________________                                                           % w/w                                                      ______________________________________                                        Isocetyl Linoleoyl Oxystearate                                                                     4.00                                                     Mineral Oil          8.00                                                     Glyceryl Monostearate SE                                                                           8.00                                                     Cetyl Alcohol        0.50                                                     Parsol MCX*          5.00                                                     Propyl Paraben       0.10                                                     Methyl Paraben       0.15                                                     Unipertan P-24**     5.00                                                     Perfume              0.25                                                     Water                69.00                                                    ______________________________________                                         *Tradename for Givaudan's 2Ethylhexyl-p-methoxycinnamate                      **Tradename for Induchem's Tyrosine complex.                             

Regarding cosmetic compositions, there may be mentioned in particular,those which are presented in the form of fluid emulsions, lotions,creams and lipstic bases. For example, the cosmetic compositions may beemollient milks or creams for face and hand care, make-up foundations,sunscreen milks or creams, antiperspirant milks or creams and shavingcreams.

While various preferred embodiments of the present invention have beenillustrated by means of specific examples, it is to be understood thatthe present invention is in no way to be deemed as limited thereto, butshould be construed as broadly as defined by the appended claims.

What is claimed is:
 1. A fatty acid ester of the formula

    CH.sub.3 (CH.sub.2).sub.5 CH(OCOR.sub.1)(CH.sub.2).sub.10 COOR.sub.2

wherein, R₁ is a straight chain hydrocarbon radical having 17 carbonatoms with 1 to 3 double bonds therein; and R₂ is a straight or branchedchain hydrocarbon radical having 5 to 22 carbon atoms.
 2. The fatty acidester of claim 1 wherein R₁ is oleyl.
 3. The fatty acid ester of claim 1wherein R₁ is linoleyl.
 4. The fatty acid ester of claim 1 wherein R₁ islinolenyl.
 5. The fatty acid ester of claim 1 wherein R₁ is oleyl and R₂is octyl.
 6. The fatty acid ester of claim 1 wherein R₁ is linoleyl andR₂ is octyl.
 7. The fatty acid ester of claim 1 wherein R₁ is linoleyland R₂ is isostearyl.
 8. The fatty acid ester of claim 1 wherein R₁ isoleyl and R₂ is isocetyl.
 9. The fatty acid ester of claim 1 wherein R₁is linoleyl and R₂ is isocetyl.
 10. A cosmetic composition comprising byweight 1-20% of a fatty acid ester of the formula

    CH.sub.3 (CH.sub.2).sub.5 CH(OCOR.sub.1)(CH.sub.2).sub.10 COOR.sub.2

wherein, R₁ is a straight chain hydrocarbon radical having 17 carbonatoms with 1 to 3 double bonds therein; and R₂ is a straight or branchedchain hydrocarbon radical having 5 to 22 carbon atoms; 5-10% of anhumectant; 0.2-1.0% of a thickener; 0.5-10% of an emulsifier; and 50-80%water.